Axial tumbler cylinder lock with pick guard



Sept. 9, 1969 J. M ILVENNY 3,465,556

AXIAL TUMBLER CYLINDER LOCK WITH PICK GUARD Filed Oct. 12, 1967 1 \l x 34 "W'- H I 3 Z8 mdmw$n-z James MaIZvenny United States Patent f 3,465,556 AXIAL TUMBLER CYLINDER LOCK WITH PICK GUARD James Mcllvenny, Chicago, Ill., assignor of one-third to Robert Gruber and Bruce Simmons, both of Chicago,

Filed Oct. 12, 1967, Ser. No. 674,910 Int. Cl. Eb 17/14 US. Cl. 70-423 3 Claims ABSTRACT OF THE DISCLOSURE A pick guard on the body of an axial tumbler tubular key cylinder lock, at its front, projects forwardly therefrom at one side of the cylinder axis and has a cavity opening to the other side of said axis to enable a proper short tubular key to be moved sidewise into the cavity to a key inserting position directly ahead of the key slot in the mechanism. The front portion of the guard provides a barrier that precludes the longer tubular shank of a picking tool from the axial alignment with the key slot necessary for insertion of the tool into the slot.

This invention refers generally to key operated lock mechanisms, and has more particular reference to improvements in cylinder lock mechanisms of the axial tumbler type, which are controlled by a key having a short tubular shank with hitting on its extremity.

Tubular key cylinder locks of the type herein concerned are sold under the trademark Gem and Ace, and are widely used on vending machines, for example, to prevent unauthorized access to the merchandise stored therein and/ or to the coin boxes on such machines.

In emergencies, locksmiths are called upon to open locks of this type with picking tools designed especially for that purpose. Such tools, as disclosed in Gruber Patent No. 3,251,206 issued May 17, 1966, comprise a tubular shank several times longer than that of the keys for axial tumbler locks, and a number of elongated spring fingers corresponding to the number of tumblers in the lock and lengthwise manipulatable in slots extending along the periphery of the tubular shank. 7,

It is inevitable, of course, that picking tools such as disclosed in Patent No. 3,251,206 eventually fall into the hands of unauthorized persons, or are made from the disclosure of the patent without the patentees knowledge. In either instance, substantial losses by theft of coins and/or merchandise from vending machines usually results.

With this problem in mind, it is a general object of the present invention to provide an improved tubular key cylinder lock of the Gem and Ace type, which features a pick guard designed especially to defeat attempts at picking the lock with a tool such as described.

More specifically, it is a purpose of this invention to provide a pick guard for tubular key cylinder locks of the character described, which guard is in the nature of an attachment that can be applied to the locks without necessitating structural changes therein.

With these observations and objects in mind, the manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawing. This disclosure is intended merely to exemplify the invention.

Patented Sept. 9, 1969 physical embodiment of the invention constructed according to the best modes so far devised for the practical application of the principles thereof, and in which:

FIGURE 1 is a perspective view of a tubular key cylinder lock mechanism equipped with the pick guard of this invention, showing the mechanism mounted upon a panel;

FIGURE 2 is a perspective view of the tubular key by which the cylinder of the lock mechanism is actuated;

FIGURE 3 is a view of the lock mechanism, partly in side elevation and partly in longitudinal section, with the key in the lock, and showing how the pick guard is mounted on the front of the mechanism; and

FIGURE 4 is a view similar to FIGURE 3, but illustrating a modified embodiment of the invention, with a special key ready for insertion into the lock mechanism.

Referring now to the accompanying drawing, the numeral 5 generally designates a tubular key operated cylinder lock of the Gem and Ace type, having the pick guard 6 of this invention in place thereon. The lock mechanism has been shown mounted on a flat panel 7, as is customary, with the body 8 of the lock projecting rearwardly through a hole 9 in the panel, and an enlarged head 10 on the body disposed at the front of the panel. A nut 11 threaded onto the body from its rear holds the mechanism in place on the panel. The body is held against rotation on the panel as by flattening opposite sides thereof and correspondingly shaping the panel hole 9.

The lock mechanism includes a cylinder 12 which is rotatably mounted in the lock body coaxially of its head 10, and which at the front of the lock mechanism, is spaced radially from the wall of a bore in the head to define an annular key receiving slot 13. Axially movable tumblers, not shown, normally coact with the cylinder to prevent rotation thereof out of a locking position. As is usual, however, the tumblers are moved to a cylinder releasing position upon insertion of the tubular shank 14 of a proper key 15 into the key slot. The key has an internal lug 14 such as seen in FIGURE 4, which engages in a keyway 16 extending lengthwise in the exterior of the cylinder, to enable rotation to be transmitted to the cylinder by the key.

The conventional key 15, for a cylinder lock such as described, has a substantially short tubular shank of a diameter to loosely telescope over the cylinder 12, and its hitting 17 is located around the periphery of its shank at the free end thereof. A flat handle 18 is fixed to the opposite end of the tubular shank to facilitate rotation of the cylinder by the key.

The pick guard 6 of this invention comprises a collar 19 which loosely encircles the head 10 and is mounted on the lock body for rotation coaxially of the cylinder 12 by means of a pair of washers 20 and 21 of equal diameter, and a spring ring 22. The washers 20 and 21 are assembled over the body 8 from its rear, and both are received in a bore 23 in the collar, opening to its rear. The collar 21 abuts the underside of the head 10, and the spring ring 22 is flatwise confined between the washers 20 and 21 with its peripheral portion loosely engaged in a groove 24 in the collar that opens to its bore. Accordingly, the washer 21 and the spring ring 22 behind it prevent forward displacement of the collar from the mechanism.

As best seen in FIGURE 3, the nut 11 threaded onto the rear of the lock body holds the washers 20-21 and the spring ring 22 between them, tightly axially confined between the front of the panel 7 and the underside of the head 10 on the lock body without, however causing any clamping force to be exerted upon the collar. This leaves the collar free to rotate about the head 10, in an orbit defined by the engagement of the spring ring 22 in the groove 23 of the collar.

The forward end of the bore 23 in the collar terminates at a shoulder 25 which faces rearwardly toward but does not necessarily have engagement with the adjacent washer 21. As shown, however, the washer 21 can have a shallow counterbore 26 in its outer face to receive a portion of the enlarged head 10 on the lock body, and to bring its outer face into contiguity with the shoulder 25 on the collar. a

On one longitudinal half of the collar, the shoulder.25 thereof comprises the rear surface of a short radially inwardly projecting flange 27 which extends over the forwardly tapered periphery of the head and defines the reaward limit of motion of the collar on the head. On its other longitudinal half, the collar is provided with a forwardly convergent wall or extension 28 that constitutes substantially one longitudinal half of a cone. The extension 28 has a cavity 29 therein coaxial with the cylinder, which opens toward the axis thereof and is shaped to nestingly receive the key 15. This is to say that the key can be readily translated sidewise into the cavity from its open side, to a defined key inserting position at which its tubular shank is directly ahead of the front of the lock mechanism and coaxial with the cylinder thereof.

The key inserting position of the key is defined partly by a semicylindrical portion 30 of the cavity which is only slightly larger in diameter than the tubular shank 14 of a key received therein, and partly by coplanar surfaces 31 on the conical extension 28 at opposite sides of the cavity, which are adapted to be flatwise engaged by one fiat side of the handle 18 on the key. The coplanar surfaces 31 are disposed in a plane spaced slightly from the cylinder axis, by a distance equal to about one-half the thickness of the key handle, so as to support the key with its tubular shank 14 coaxial with the cylinder 12 and key slot 13.

The semicylindrical cavity portion 30 in the pick guard opens rearwardly to a conically shaped recess 32 which, in turn, opens rearwardly to the bore 23 in the collar. Hence, it will be seen that the conically shaped recess defines the inner edge of the flange 27 at the front of the collar. The semicircular portion 30 of the cavity also communicates with a forwardly convergent recess 33 at the front extremity of the pick guard, shaped to fit the reduced and substantially bullet-shaped end of the key shank at its junction with the handle 18.

It is important to note the the flat surface areas 31 on the guard extend around and across the front end 34 of the pick guard to have engagement with one fiat side of the key handle at a location slightly forwardly of the adjacent bullet-shaped end of the key shank 14. The end 34 of the pick guard thus not only provides a barrier that prevents straight coaxial insertion into and/ or removal of a proper tubular key from the lock mechanism, but more important, the barrier precludes any possibility of coaxially aligning the much longer tubular shank of a picking tool with the cylinder and key slot. This results from the fact that the surface 31 at the front 34 of the guard is so close to the axis of the cylinder that it will cause the longer tubular shank of any improper key or picking tool to be disposed at such an angle to the cylinder axis as to most effectively prevent its insertion into the key slot.

It will also be noted that the fiat key handle 18, by its engagement with the flat surfaces 31 on the pick guard, is able to transmit rotation to the guard during locking or unlocking of the mechanism.

The modified pick guard 6' shown in FIGURE 4 features a collar 19 that is fixed against rotation relative to the head 10 of the lock mechanism, and requires a special key 15. As therein seen, the collar 19 can be tightly nonrotatably clamped against the front of the panel 7 merely by elimination of the washer 20. In this case also, the guard has a small semicylindrical recess 36 which opens through its front 34, to freely rotatably receive a cylindrical stern part 37 on the key that joins its handle to the tubular shank thereof. The handle, of course, always lies entirely forwardly of the fiat surfaces 31 on the guard in this embodiment of the invention, to allow the key to rotate relative to the pick guard.

From the foregoing description, together with the accompanying drawing, it will be readily apparent to those skilled in the art that this invention provides a pick guard that most effectively prevents unauthorized unlocking or picking of a tubular key cylinder lock of the Gem or Ace types by picking tools presently available.

What is claimed as my invention is:

1. An axial tumbler cylinder lock mechanism having a body in which the cylinder is mounted, and wherein a key having a short tubular shank is insertable into an annular key slot, in telescoping relation to the front of the cylinder, to free the cylinder for rotation to an unlocking position, characterized by:

(A) a collar encircling and mounted on the front portion of the body;

(B) means on the front portion of the body supporting the collar for free rotation relative thereto about an axis substantially coincident with that of the cylinder;

(C) cooperating abutment defining means on the front portion of the body and on the collar to prevent forward displacement of the collar from the body;

(D) and wall means fixed on the collar and projecting forwardly therefrom at one side of the cyilnder axis to provide a pick guard having a key receiving cavity therein which is coaxial with the cylinder and which opens laterally to the opposite side of the cylinder axis,

said wall means having a barrier portion at its front which extends crosswise of and close to the cylinder axis at a distance from the front of the lock mechanism only slightly greater than the length of the tubular shank of a proper key so as to require sidewise movement thereof into said key receiving cavity from the open side thereof and to block axial motion into the key slot of a picking tool having a tubular shank longer than that of a proper key,

said pick guard comprising one longitudinal half of a hollow cone having the collar as its base, and having forwardly convergent edge portions lying in a common plane parallel to and spaced from the cylinder axis a distance sufficient to accommodate a fiat handle on a proper key for the mechanism and to support the key handle with the tubular shank of the key substantially coaxial with the cylinder,

whereby rotation will be transmitted to the collar by the key through the flat handle thereon.

2. The lock mechanism of claim 1, wherein said collar has means thereon to engage the front portion of the body and prevent rearward displacement of the collar therefrom.

3. An axial tumbler cylinder lock mechanism having a body in which the cylinder is mounted and which, in turn, is securable in a hole in a panel upon tightening of a nut on the body against the rear of the panel, and wherein a key having a short tubular shank is insertable into an annular key slot, in telescoping relation to the front of the cylinder, to free the cylinder for rotation to an unlocking position, characterized by:

(A) a collar encircling and freely rotatably mounted on the front portion of the body;

(B) cooperating abutment defining means on the front portion of the body and on the collar to prevent forward displacement of the collar from the body,

5 6 portions of the abutment defining means on the thereof and to block axial motion into the key body projecting rearwardly beyond the collar slot of a picking having a tubular shank longer for engagement with the front of a panel on than that of a proper key; and which the lock mechanism is mounted to prevent (D) force receiving means on said picked guard posithe collar from being nonrotatably clamped to 5 tioned to be engaged by a part on -a key in place in the panel upon tightening of the nut securing the the lock mechanism to have rotation transmitted lock body to the panel; thereto by the key. (C) w all means fixed on the collar and projecting forwardly therefrom at one side of the cylinder axis to References Cited provide a pick guard having a key receiving cavity 10 UNITED STATES PATENTS thereln which is coaxial with the cylinder and WhlCh opens laterally to the opposite side of the cylinder 2:235: 3 7551 was,

said wall means having a barrier portion at its 3343386 9/1967 Han 70-423 front which extends crosswise of and close to the cylinder axis at a distance from the front of 15 MARVIN CHAMPION Pnmary Exammer the lock mechanism only slightly greater than R. L. WOLFE, Assistant Examiner the length of the tubular shank of a proper key so as to require sidewise movement thereof into US. Cl. X.R.

said key receiving cavity from the open side 20 7 5 mg UNITED STATES PATENT OFFICE ,ERTIFICATE OF CORRECTION Fe tent No. 3, 465 556 Dated September 9, 1969 Inventor(s) m'lY it is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 2 picking having" should read plcxlng tool having Column 6, line 4 "picked" should read e pick- LnJ SEALED FEB 1 71970 Attest:

Bambi- WILLIAM E. mm, JR- Officer Oomnissio'ner of Patents 

